This invention relates to articles in which a tobacco flavor medium is heated to release tobacco flavors. More particularly, this invention relates to an electrical smoking article in which the tobacco flavor medium is a liquid.
Electrical smoking articles are well known. Such articles generally include a plurality of electrical heating elements disposed adjacent tobacco flavor medium containing, for example, tobacco or tobacco-derived material. In such smoking articles the plurality of heating elements can be either disposable (see, e.g, commonly-assigned U.S. Pat. Nos. 5,060,671 and 5,095,921, which are hereby incorporated by reference in their entirety) or permanent (see, e.g, copending, commonly-assigned United States patent application Ser. No. 07/943,504, which is hereby incorporated by reference in its entirety). The tobacco flavor medium may be, for example, a solid material that is inserted into a cavity of the electrical smoking article. If the heaters are disposable, then the tobacco flavor medium would be deposited on the electrical heating elements that are inserted. After a finite number of "puffs" on the article by the smoking (e.g., eight or ten), the tobacco flavor medium, along with the electrical heating elements if disposable, is removed from the cavity and replaced with fresh tobacco flavor medium (and heaters).
It has been found that with the types of electrical smoking articles described above, the number of puffs available to the smoker for each loading of tobacco flavor medium is generally limited by the number of heating elements in the smoking article. For example, if the smoking article has eight heaters, then a smoker will derive eight puffs before having to replace the used tobacco flavor medium with fresh tobacco flavor medium (and heaters).
Additionally, because the above smoking articles have a plurality of heaters, the design and manufacture of such smoking articles can be complicated. For example, the plurality of heaters generally must be spaced sufficiently far apart from each other that each heater is thermally isolated from the other heaters. Also, the total number of heaters that can be placed in the smoking article may be limited since increasing the number of heaters generally results in an increase in the volume of the smoking article.
Furthermore, the physical arrangement of the plurality of spaced-apart heaters may also complicate placement of the tobacco flavor generating material which generally must be placed in thermal communication with each heater. In particular, the shape and construction of the tobacco flavor medium may be limited by the arrangement of the plurality of heaters. For example, the tobacco flavor generating material would have to extend over a volume that reaches each individual heater. This can result in the use of a greater volume of tobacco flavor generating material than is actually heated by the heaters and, thus, may result in the waste of tobacco flavor generating material that is not heated. Also, such excess tobacco flavor generating material may serve as a heat sink which may unnecessarily increase the power consumption of the article.
In light of the above, it would therefore be desirable to be able to provide an electrical smoking article in which the number of puffs from the smoking article is not limited by the number of heating elements.
It would also be desirable to be able to provide such a smoking article in which the design and manufacturing of the smoking article is simplified.
It would further be desirable to be able to provide such a smoking article in which the amount of tobacco flavor medium that is wasted is reduced.